A shunt is a tiny plastic tube that connects a fetal body compartment (typically fluid surrounding the lungs or a very large bladder) with the amniotic sac, so that the fluid can drain into the amniotic sac. These shunts are inserted through a special needle under ultrasound guidance.

Fetal shunt procedures are usually done under local anaesthesia (freezing injected into the skin). The mother also receives intravenous (IV) medication to be relaxed during the intervention and IV antibiotics, but does not sleep during the procedure. We ask mothers to fast (i.e. NOTHING to eat or drink) for at least 8 hours prior to the procedure.

Before fetal viability (~ 24 weeks), shunts procedures are done on an outpatient basis; after viability, the mother is admitted to hospital for a few hours, however can usually go home a few hours after the procedure.

The Fetal Medicine group at Mount Sinai hospital has one of the largest experiences in the world with fetal chest shunt insertion.

What fetal conditions can benefit from the insertion of a fetal shunt?

Shunt procedures can be done for any condition that causes an excess of fluid to accumulate within the fetal body. Examples are large fetal pleural effusions (fluid in the chest), large cystic chest masses or bladder outlet obstructions.

What are the risks of the fetal shunt insertion for the pregnancy?

The main risks of fetal shunt insertion are breaking the water early (PPROM: preterm premature rupture of membranes) and preterm labor. The average gestational age at delivery after shunt insertion is 35 weeks. Fetal shunts may also become blocked or displaced. Therefore close ultrasound surveillance, every 1-2 weeks, after shunt insertion is required. Depending on the reason why the shunts are inserted, additional risks may be present. These are discussed under the specific conditions.

What are the risks of fetal shunt insertion for the mother?

The risk of infection after fetal shunt insertion is very small, but usually antibiotics are administered preventatively prior to the procedure. Fetal shunt insertion does not permanently damage the uterus and is not a reason in itself to deliver by caesarean section. Fetal shunt insertion does not affect a mother’s long-term health or her future fertility.